In the field of the industrial mincing of meat, grinders are used that each essentially comprise a feed hopper ending into a room in which acts an endless screw which pushes the meat towards one or more cutting assemblies, each comprised of a star-shaped cutter with several legs, whether curved or not, and a grid having more or less large openings. For each of the cutting assemblies, the cutter can freely rotate on the grid and, eventually, within the two grids surrounding it, when such is the case, said grid or grids being capable of being immobilized within the grinder, while a shaft is capable of rotationally driving the cutters through which it passes, by being connected to the latter in rotation through at least one flat surface, while one of its ends is connected to driving means and the other end rotates in the bearing block of a supporting grid or spider.
Furthermore, devices are known which allow to sort the meat, i.e. to separate from the hard components, which are essentially the cartilages, the tendons and the nerves. These separating devices are intended at being optionally arranged at the outlet of the grinder.
The most effective one of these devices consists of a grid associated with a separating cutter which is also star-shaped with several legs, whether curved or not, each one including, on one surface, parallel ribs forming an angle with the radial axis of the leg. The ribs are intended at coming into contact with the grid, in order to scrape the latter and, because of their orientation, to drain towards the center the hard components which do not pass through the grid. The hard components pass between the separating cutter and the grid to arrive into the central hole of the latter, between the latter and the driving shaft, said central hole having, to this end, a diameter much larger than that of said shaft. According to a variant, a collecting tube is screwed into the supporting plate and is inserted into the central hole of the grid at an adjustable depth, with a possibility of blocking, in order to adapt its position with respect to the separating cutter. The collecting tube is, furthermore, connected to a discharge pipe for the hard components.
Such a device has however many disadvantages, in addition to dysfunctions and a sometimes poor result, fast wear of the cutters and grids is observed.
Indeed, when a separating device is fitted on the grinder, the separating cutter is not designed so as to rotate in the grid in order to allow the passing through of the hard components, which eliminates means for holding said cutter, while the end of the driving shaft is no longer held, because of the replacement of the bearing block by the collecting tube. Therefore, the transversal hold of the end of the shaft is not ensured, which results, because of the many constraints which the separating cutter is subjected to and which are increased when the meat is frozen, into movements of the separating cutter with respect to the grid, which generate a premature wear of the latter.
In order to cope with this disadvantage, there has been proposed, in addition to holding the end of the shaft from the outside, as in U.S. Pat. No. 5,417,376 and U.S. Pat. No. 5,443,214, to replace the grid and the collecting tube of the separating device by a grid provided, externally, with an end adapter for coupling a discharge pipe for the hard components, and which is perforated with holes distributed over the periphery of the seat in which the end of the driving shaft rotates, in order to end into said coupling adapter. The end of the shaft is thus held and the hard components can pass through the grid and be evacuated into the discharge pipe. Such devices are provided in U.S. Pat. No. 4,97B,077, U.S. Pat. No. 4,699,325, U.S. Pat. No. 4,202,502 and U.S. Pat. No. 4,795,104, and they all have the same disadvantage, that of not allowing an easy adjustment of the selection of the size of the hard components to be evacuated.
In order to cope with this disadvantage, FR 2,474,342 provides a grid also perforated with holes over the periphery of the seat in which the end of the driving shaft rotates, while the collecting tube is held externally against said grid and has holes which, according to the angular orientation of said tube with respect to said grid, are likely to be more or less closed, in order to control the size of the hard components. This device has however another disadvantage, indeed, the adjustment of the selection of the size of the hard components occurs downstream of the grid, which gives rise to frequent clogging incidents and requires interventions.